Tuesday, September 21, 2010

How Frankfurt's example refutes compatibilism

(Premise) Frankfurt's example shows that if compatibilism is true, then the Principle of Alternate Possibilities is false.

(Premise) The Principle of Alternate Possibilities is true.

Therefore, compatibilism is false.

Of course, Frankfurt's example was meant to show that whether or not compatibilism is true, the Principle of Alternate Possibilities is false. But because, as has been shown for instance by Widerker, the example assumed the existence of a sign that determines one to engage in a particular action, the argument failed. (There are variants on Frankfurt's example that have been proposed that fix the problem, but whether they succeed is controversial.) However it is easy to see that Frankfurt's example has refuted compatibilist versions of the Principle of Alternate Possibilities (e.g., Hume's version on which if x freely does A then had x wanted not to do A, x would not have done A).
It is worth noting that (2) was accepted by classic compatibilists like Hume and Ayer (with a compatibilist reading of "able to do otherwise"). Of course, they might well have abandoned the Principle of Alternate Possibilities given Frankfurt's example. But perhaps they shouldn't have. For the Principle is deeply plausible. Instead, they should have abandoned compatibilism.
A potential response is to modify the Principle in a flicker-of-freedom way. This is open to compatibilists as well as incompatibilists.

3 comments:

1.(Premise) Frankfurt's example shows that if compatibilism is true, then the Principle of Alternate Possibilities is false.

Does it show that? It's hard to see how. First, are there compatibilists who reject every version of PAP? Take Lewis, for instance. He argues in typical compatibilist style that determinism does not entail that you can't do otherwise. Even if it is determined that I don't raise my hand, it is true that I can raise my hand, and os it is true that I can do other than what I am determined to do. Now consider Frankfurt. Is it true that I cannot do other than what I'm caused to do? No. I can do otherwise. It's just that, were I to do so, it would be the case the laws/history are different. So, I'm not sure how Frankfurt shows that 'can do otherwise'--in a sense that compatibilists find appealing--fails in the Frankfurt cases. That is, I'm not sure unless some version of the consequence argument is sound (but none are).

I think that cases where you're physically forced to do something by direct manipulation of your brain are paradigm cases of not being able to do otherwise, in a way that is not in dispute between typical compatibilists and incompatibilists. But the Frankfurt case is relevantly similar to cases wehre you're physically forced, except that in the actual sequence there is no forcing.

The same line about how the laws/history would have been different could be run in cases where you're physically forced. Let's say you've got electrodes implanted in your brain that directly determine every movement. If we allow the laws and history to have been different, "you could act otherwise". But that isn't the contextually relevant kind of "could act otherwise" that both the compatibilist and incompatibilist mean.

Here's another paradigm case. You're in a locked room, and there is no key, and you have neither the ability to pick the lock nor the strength to break the door, etc., etc. I take it that everybody wants to say that in the sense of "could" relevant to free will and responsibility, "you could not leave the room." But of course if the laws/history were different, you could.

"Could" is context sensitive. Compare: "I could easily walk 10 miles in a couple of hours" and "I couldn't get to my doctor's appointment (10 miles away) because my car wasn't working and I couldn't afford a taxi" can be both true. In one kind of context, walking 10 miles counts as "possible" and in another, it counts as "impossible".

But PAP itself provides a certain kind of context, and it is a context that rules out external physical forcing of the brain.

I'm stunned to hear you say that 'can' is context relative. I don't think you can hold that Lewisian view and be an essentialist (Lewis abandoned essentialism at this point). But I agree that it probably is context relative, and I struggle with my essentialist intuitions.

I guess I'm not following what you say here,

I think that cases where you're physically forced to do something by direct manipulation of your brain are paradigm cases of not being able to do otherwise, in a way that is not in dispute between typical compatibilists and incompatibilists.

These are not so different from traditional contexts in which the facts and laws cause you to act. Why would direct manipulation matter other than rhetorically? I'm not seeing it.

The Lockean case of being locked in a room most compatibilists would agree involves a loss of freedom, but that has nothing to do determinism or being caused to act in certain ways. It is because you are being restrained or constrained, which compatibilists are happy to allow is inconsistent with being free.

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